List of Articles magma mixing

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  1 - A study of different zoning types in clinopyroxenes of sodic and potassic alkaline volcanic rocks from North Lahrud, NW Iran
  Gholamreza Ahmadzadeh Reza Zamani
  Clinopyroxene phenocrysts and microphenocrysts in potassic and sodic Eosen alkaline volcanic rocks from the northern Lahrud (NW Iran) record various stages in the crystallization and evolution history of the alkaline melt as well as its origin. The rock series hosting t More

  Clinopyroxene phenocrysts and microphenocrysts in potassic and sodic Eosen alkaline volcanic rocks from the northern Lahrud (NW Iran) record various stages in the crystallization and evolution history of the alkaline melt as well as its origin. The rock series hosting the clinopyroxene phenocrysts is phonolitic tephrite and tephritic phonolite composition. Theses rocks generally show porphyritic texture and have a variable phenocryst-rich nature (25–50%), with phenocryst assemblages characterized by Cpx ± An ± Pl. The studied clinopyroxenes have relatively high Mg-numbers (0.66-0.90), variable Al2O3 (3.77-7.31 wt%), low TiO2 (<2.02 wt%) and Na2O (<1.23 wt%) contents and low AlVI/AlIV ratios (mostly <0.25), suggesting relatively low-pressure crystallizing conditions of the magma in the magma chamber. The calculated pressures for the clinopyroxenes in these rocks vary in the range of 4–5.5 kbars. Oscillatory reverse zoning of clinopyroxenes related to the different crystallization paths under a variable oxygen fugacity and different oxidation conditions and sudden pressure differentiation and magma mixing processes. Normal zoning related to the differentiation and fractional crystallization of the magma. The resorption texture of core parts of some clinopyroxenes are attributed to the changes of crystallization pressure though such textures have been ascribed to magma mixing.  Manuscript profile
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  2 - Petrography and petrology of latest stage of Savalan volcanic rocks
  Mahnaz fathollahi mohamad hashem emami monireh kheyekhah
  In the latest stage of Savalan volcano formation, the Magmatism following the Subsidence of caldera Cause theformation of acidic and intermediate Dooms and viscose lava flows along fractures and within the margin ofCaldera. mainly having composed of plagioclase, clinopy More

  In the latest stage of Savalan volcano formation, the Magmatism following the Subsidence of caldera Cause theformation of acidic and intermediate Dooms and viscose lava flows along fractures and within the margin ofCaldera. mainly having composed of plagioclase, clinopyroxene, amphibole, biotite, potassic feldspar andquartz, Textural and mineralogy relations that are observed in studied microscopic sections, such asglomeroporphyric and glomerochristic occurrence of Mafic minerals as well as the presence of non equilibriumtextures such ac sieve texture, bimodal composition of phenocherists of plagioclase, heterogenic composition ofmatrix, presence of basic micro pillows and enclaves in a acidic rocks, zenolites with reactional rims and alsoscattering and different trends observed in the geochemical reveals that fractionation, magma mixing and crustalcontamination has been play important role in formation of this magmas. On the other hand The intermediaterocks of the region form do to of the mixing of basaltic magmas with fractionated sections , that have beencontaminated with Crust during the ascent phase. Base on Petrographic and geochemical evidence presentedhear, we show that the acidic rocks vastly in the area have a different origin than andesitid and trachy andesitidlavas. Likely that these rocks are the result of partial melting of the crust, while the replacement of basic magmasin crustal magma mixing phenomena has also been made between the two. Manuscript profile